The present invention relates to prostatic surgery and more particularly to a computer guided system for focal, nerve sparing ablative surgery.
Ablative surgery of the prostate is an effective treatment for prostate cancer. There has been a focus in prostate cancer treatment development in trying to improve the quality of life of patients by limiting the effect of treatment on patient sexual functioning. For example, Littrup et al, in Prostate Cryosurgery Complications, Seminars In Interventional Radiology, Vol. II, No. 3, September 1994 discuss a protocol for potential nerve-sparing prostate cryosurgery for patients with evidence of unilateral disease. Littrup et al propose altering the placement of cryoprobes and close monitoring of the iceballs formed therefrom for patients with evidence of unilateral disease on standard systematic biopsies, followed by negative subcapsular biopsies. The cryoprobes are shifted toward the ipsilateral tumor side, leaving the potentially spared contralateral tissue.
There is reference in the prior art to the use of computer control systems for providing and/or enhancing cryosurgical techniques. For example, U.S. Pat. No. 4,672,963, issued to I. Barken, discloses an automated and integrated system including a cryosurgery device, an imaging probe and a computer system for use in performing internal surgery. U.S. Pat. No. 5,647,868, issued to D. O. Chinn, discloses another cryosurgical integrated control and monitoring system.
U.S. Pat. No. 6,139,544, issued to P. W. Mikus et al, discloses a system for assisting surgeons in performing cryosurgery of the prostate by calculating optimal positions for cryoprobes and providing display based templates for overlay over an ultrasound image display, and displaying actual cryoprobe ultrasound images together with template images so that the surgeon may compare suggested and actual placement of the cryoprobes, and adjust placement accordingly.
In one broad aspect, the present invention is a computer system for the focal treatment of prostate cancer. The computer system is capable of acquiring and displaying images of the prostate of a patient for assisting a surgeon in placing ablative elements in the prostate of the patient. The computer system is programmed with software capable of determining the dimensions of the prostate, determining the dimensions and location of a treatment zone; and, utilizing the determined dimensions of the prostate and treatment zone for computing the number and location of ablative elements needed to treat the treatment zone while minimizing any adverse effect on the patient""s sexual function.
The step of utilizing the determined dimensions of the prostate and treatment zone, preferably comprises the steps of:
computing the number of ablative elements;
computing a distance (b) between the ablative elements so that the ablative elements are
placed approximately equidistant from each other in the treatment zone;
computing a first position for placement of a first ablative element;
computing a second position for placement of a second ablative element, the second
position being at the distance, b, from the first position and a distance a from the prostate
periphery, wherein a is approximately xc2xd b; and,
computing N-2 remaining positions for the ablative elements in substantially the same
manner as the second position was computed.
The computer system is particularly adaptable for use in instances where a biopsy has indicated that unilateral ablative nerve sparing is warranted. In such instance one side of the prostate, including its associated neurovascular bundle is spared while the other is sacrificed. This can maintain potency for the patient.
Although particularly adaptable for use with cryoprobes, the inventive concepts disclosed herein can be utilized with other suitable ablative elements, as discussed below, that can provide the desired ablation.